Ha-wqkichi tajffaka



N. TMIAKA.

CRANK PISTON CONNECTOR.

APPLICATION FILED MAR.14, 1910.

Patented July 15, 1919.

N. TANAKA. CRANK Hsmi CONNECTOR.

APPLICATION FILED MAR. 14, I919.

Patented J My 15, 1919! 2 SHEETS-SHEET 2.

, nector.

Y struction.

HARVOT'ZIQHE nugThzz-m m,

Specification. of Letters Patent.

epplicat-ien filed filer-2h re, 1919. Seriai It 0. 282,2/19.

To all whom it may concern;

Be it known that I, NAWOKIC'HI TANAKA, a subject of the Emperor ofJapan, residing at Boston, in the county of Suffolk and Commonwealth ofMassachusetts; have invented a new and useful Crank-Piston Conof whichthe following is a specification. I

This invention relates ton crank-piston connector of variable connectionlength, in which a connecting rod hes a housing or hearing for cams, andsaid cums 1 Mine; specificnll'y prepared form an integral part of ecrank-pin, and, rotating" as the crank turns, are adnptecl to move saidhousing reciprocally relatively to the cznn axis, in response to changeof the inclination of the connector to the crankthrow carrying saidcrank-pin. and the vi.- rintion of the connection length is therebyCZHlSQd to effect an advantageous piston movement with respect to theuniform revolntion of the crank shnit.

With connecting means of ordinnrv conthe piston movement tliiiers in theopposite strokes, as the crank-shaft nnifol-ml); rotates, and it appearsrobe impossible to obtain the initial slow movement of pistonsdesirable, if not requisite. for a high speed engine, and furthermore.the tlesircci slowing-down or speeding-up of piston movement nt certainstage of a stroke for utilizin;- the expansion energy more efficientlyis, if possible a (liliicult matter to attain. The present inventioninninl} minis to provide snnnle incnns for joining 1: connecting root ton crank-throw whereby the engine ehciency is improved on these points.or in other words. my invention has for its object, first, to reducepower WISiiG in engine cylin ens or otherwise improve engine eliiciency;Second, to provide :rsimpie and ctlicient connector for :1 piston andcrank wherebytheir 7 relative movement is modified; thirth to reduce oreliminate the torsional to the (lilt'erence of opnositc piston strokes.Further objects of the invention are the provision of cams which notcorrelatively on vibration (inc opposite sides, responding to thechzinire of the inclination of :1 connector to its chinkprofiles aremounted on 01" understood to be throw; the employment of cams, actingwith their shaft or circular members mounted therewith, capablepositively to impart re-' eiprocating movement to-the housing, thereof;and the provision of an oil-containing housing therefor.

"With the above nd other objects in View, my invention comprises certaindetail of construction and arrangement of ports :is will he hereinaft rmore fully described, illnstratednnd Cil21l..\i(l.

The invention will be best understood by referring the accompanyingdrawings which form a part of this specification and in Which Figure l apart sectional View of a crank-piston connector, in connection withcrank part. embodying my invention;

Fig. 2 is a side View of the SZLRDQ, the pnrtf section therein heingtoken Along line A A or i Lend line B .8 showing where the part sectionof Fig, 1 is traced:

Figs. 3. 4, and 5 show how I obtain the cum forms appearing in Fig. 1;

Figs. 6 and T depict a geometrical Way to determine cinn profilessuitable for high and Im' speed engines;

Figs. 8 and 9 illustrate how the cam pro files may he modified when usedfor an of?- set-engine; and

Figs. 10 and 11 set forth a. way how to draw the cam profiles withpurpose to 0btziin certain piston recesses for on engine.

Sin'iilnr numerals and characters indicate corresponding partsthroughout SCVQiAl views.

Referring to Figs. 1 and 2, rod whose upper 2 designates e portion isomitted hut is connected with :1 piston in one of the known or therodiorrns a. cam housing 3%. These parts are preferably cast. or forgedin two manners. The lower part pieces. and tne lower half 4 is holt liothe upper half 3 of the housing which is integral wilth the rod portionas shown. Within the housing 3%, there is located av crank-pinwhichcomprises a inaincnm 5., auxiliar cams 5. and circular plzites 'i', 7,all rigid with their shaft. 8. This *crnni zpin is in z'igil connectionwith crank-Webs- (ill 9, 9 a crank or crank throw) and crankshaft 10,and may be cast or forged together therewith. the cam part beingproperly machined thereon or otherwise secured therewith.

The housing has two somewhat elliptical openings 11, ll admitting thecam shaft 8 to pass through and to allow certain relative reciprocatingmovement thereof as later will be referred to. These openings areprovided with bushings 12, 12 of white metal or comparatively soft metalon which the cam shaft is to slide.

To make the cam housing a lubricant container, these openings 11, 11 aresubstantially closed by the circular plates 7, 7 which have retainingedges or bosses holding in the place white metal washer rings 13, 13against the housing wall. The washer rings are made in halves, if thewhole crank shaft is made in one piece, and may be held rigid with theplates or rotatably in the bosses. Simplicity and durability in view, Iprefer the above construction; however, the circular plates'T, 7 may berotatably mounted on the cam shaft, when desired, with washers againstthe cams (3, 6. l urthermore, the circun'iference of the plates may bemade large enough to reach the side wall of the housing so to share withthe cam shaft the burden imposed by the lateral thrust of the housing.

In engagement with the main cam 53, an anti-frlction roller 14- wlth itsshaft is held in its bed on the upper inside wall of the housing, whilethe lower wall is provided with beds for other rollers 15, 15 which areadapted to engage with the auxiliary cams 6, 6 and are joined by a shaft16. As will be depicted later, these rollers are adapted to roll intheir beds, for the profiles of the cams are such as to keep themsubstantially at a constant distance. The sidewise movement of therollers is resisted by the bed walls which are in contact with the endsof the rollers. As these rollers are removable, when a renewal isrequired they may be made of softer metal than the cam profiles thoughnot necessarily since they can be kept in an oil bath. The use of thetwo auxiliary.

cams is apparently for obtaininga symmetrical balance, and the number ofthese two kinds of cams and the arrangement thereof may be otherwise. ifdesired. As the auxiliary cams (3, l) operate under less stresses thanthe main cam 5, they are made to have less contact surface to save spacefor the latter. 17 indicates an oil cock.

I have shown herein anti-friction rollers as the cam followers; however,should simplicityand lightness he more important, the lower rollers maybe substituted by an equivalent. convex surfa e of the housing wall. andeven the upper roller may be dispensed with by similar substitution.

In Figs. 3, 4, and 5, a geometrical way to determine cam profiles for ahigh speed engine and for a symmetrical piston movement is depicted. Thecam profiles are so related to each other, as to keep continuoussubstantial contact on opposite sides with the contact surfaces of thehearing, or with the rollers as in this case.

Referring to Fig. 3, the broken. semicircle indicates part orbit of a.crankpin around the crank axis 7/, and is cut by a number of radii(there are only seven shown for the sake of clearness) which divide thesemi-circle equally, but which may be taken at random greater the numberbeing better for accuracy. The broken horizontal lines are sine lines tothe vertical diameter ccl. This diameter being equal to the piston passthe intersections are transcribed onto the latter. Each of these pointson the piston pass c7' is connected with the corresponding point on thesemi-circle, representing the position of the connector. Subtracting theconnection length cc at the top center from every other, an incrementoflength required at each stage of the connector movement is found for asymmetrical piston movement. This data and the angles or inclinationbetween the connector and the crank-throw represented by the radii arethe needed data for forming the cam profiles.

'lransplauting these angles on the lefthand side of the vertical line rh of Fig. f, measuring therefrom with g as the center of radiation, aseries of radial lines are obtained. In this case, the connectorposition on the left half of the crank-pin orbit is symmetrical to thaton the other half, so the angles are copied symmetrically on the righthand side of the line /1.. f/ as the center, a circle of suitableradiusis circumscribed,cutting the above radial lines. Outwardly fromthese intersections, I find a point on each line at a distance, equal tothe sum of the radius of a roller (which is to be employed as the camfollower) and the increment (algeln'aically, if it is decrement) ofconncction length at that stage. \Vith these points as the centers andwith the radius of the roller, a series-of arcs are drawn inwardly,rlmrescntiug the position of the cam follower at each stage of the crankmovement. A closed curve made tangentially to these arcs represents themain cam profile.

in Fig. 5, the radial lines obtained as above are turned 180 degrees.and a solid circle is circuinscribed ,whose radius. though may have anysuitable length. is made greater than that of Fig. 4 b v the incrementof connection length at. the mid-strok of the piston in orderto havecams of same size. From the points where this circle cut the radiallines, the centers of arcs are found at a dist ancc outwardly equal tothe radius of a roller minus the increment (algebraically, if it isdecrement) of connection length at the corresponding stage. In the drawings, the diameters of the two rollers are taken equal, but they may bedifferent when desired. As before, arcs and a closed eurretangent-iallyto the arcs are drawn. This closed curve represents theauxiliary cam profile.

Ash is readily understood, when the two curves set one over the other,with g as their common center and with the direction as it appears'inthe drawings, ever 7 two corresponding radial lines onto. wlnch equalincrement was carried oppositely are on opposite sides, andconsequently, when two cams harmony. However,

provision, the circular having such curved profiles are mounted on acommon shaft, and two rollers having the given'radii as above are madeto roll on the cams (inexact opposite sides, one roller in. contactWithone, "n onlggas seen in Fig. l, the distancebetwe nth'e rollers isconstant and the rollers follow the cam profiles in in applying topractical. use, certain clne allowance for thermal expansion and for oilpassage is to he made by usin a slightly larger radius for the arcs indetermining the cam form.

The cams thus determined. when forged or machined on a crank pin, havethe lower side of the cam forms toward the crankshaft axis (see Fig. 1).

If simplicity is preferable to the oil-tight plates 7, T and the rings13, 13 may be dispensed with, substituting simple washers in lieu. A

Although 1 have herein shown cani followers with convex surface aspreferred, they may have flat surfaceor even concave, withcorrespoiulingi' change in cam profiles.

in operation, a piston in connection with this device, after leaving,'its upper center in an expansion stroke, weighs upon the main earn 5through the upper roller 1%., thereby turning the crank-throw downward,and the crank-turn ni'eans the rotation of the Gains in the samedirection. Since the rod is pirotally held by the piston, it does notturn with the cams, but the rollers roll on respec tive cain profiles,the upper roller I l up a slight gradual inclination on the main cam 5.and the lower cam axis in contact with the-auxiliary cams l), (3,duringthe Iii-st 90 degrees of the crank rotation. Assuming the crankturns clockwise, this action of the roller ll exerts side pressure onthe left. side of the cam-shaft (and that of the circular plates 7, 7.,it". the plates have their circumferences in contact with the housingwall), and works" oppositely to the side thrust of the piston to itscylinder. This movement of the rollers gradually shifts the housing 3-lupward.

relativelg to the axis of the cam-shaft, thereridcs on rollers. l5, 15toward the,

by increasing the connection length between the piston and the (I'2l1il-]')i1i axis, while the rollers maintain a constant distancetherebetween. is explained referring to Figs. l. and 5, substantially incontinuous contact with respective cams.

When the roller l reaches the left apex of the main eani 5 after 90degrees of crank rotation, the piston is found at the middle of thestroke (in the present case). During the other half of thestroke, theroller ll gradually falls back toward and the rollers 15, 15 are drivenaway. from. the cam axle, allowing the housing to more downward,relatively to the cam sliai tfand therefore reducing the c n1ncctionlength. until the lower center is reached, when the comwol lbn length isthe. same as at the upper center and when the rollers l5. l5 confrontthenarrower ends of the cams ll, 6. This completes a cycle ofreciprocatory movement of the housing with respect to the cam shaft. Inintake strokes of piston (when used in a four cycle engine), theperformance is the same as aliorc, cxccpt'the active agents fortransmitting power are the cams l5, (3 and the rollers 15. 15, as thecrank leads the piston.

in I'Cilii'l). strokes (compression and exhaustion strokes}, the turningof the coins upon the housing in similar manner, forcing the housingupward and then downward with respect to the canrshaft, or increasingand then decreasing connection length through the upper roller ll whichthe other apex of cam 5, when the piston is at its niid-stroke,.or at 90degrees of the crank rotation from either center. At the upper (leadcenter, the cams and hence the housing resunie the initial position,thus the housing completing another cycle of reciprocatorv motion.

The foregoing e planation is easily understood by COliSl ering the formof the cams in respect to rollers and the relation thereof to the crankand the rod, as already described It idily appare .t from the above deiition, that by properly modifying the cam profiles, the relativeposition of the piston and the cranlepin at an y stage of stroke can hecl angled as desired within a practical limit, by changing the positionof the crankpin with respect to corresponding position of the piston indetermining cam profor example, some of the other canrfornis aredepicted in Figs. 5 t 11 inelusive. However, these are fundamental formsfor obtaining the similar movement of a piston in opposite strokes, and.as is understood from the illustration herein, the distance betweenpoints on the piston pass shows comparative speed at that part-of pistonstoke, when the crank shaft is rotating Uniformly. Therefore it requiresno explanation in stating that by shifting the position of these pointsone way or other or by modifying the distance therebetween in formingcam profiles, piston speed at a given stage of a stroke may also beaugmented or diminished.

If the connection length between the piston and crank-.pin be invariableas in the case with a customary connecting rod, the movement of pistonis different in opposite strokes with the uniform rotation of thecrank-shaft, the piston traveling faster during the upper 180 degrees ofcrank rotation than during the lower 180 degrees, and when the crank-pinis at the midway between the dead centers. the piston can not be at themiddle f its pass, unless the connecting rod has infinite length, butwill be at a position nearer to the bottom center.

lVith the present provision. the relative movement of the piston andcrank-pin is so modified that their vertical rectilinear motion is madeequal (with the cams depicted in Figs. 4 and 5). It follows that thepiston is made to travel slower than with a usual connecting rod duringthe upper half of crank rotation, and the acceleration of piston speedat the upper half of power strokes is made smaller so as to meet withthe requirement in high speed engines.

.In Figs. 6 and 7, cam profile forming is shown for still higher orlower speed engines. In order to obtain low initial speed for a highspeed engine, or high beginning speed for a low speed engine. and. atthe same time, to secure similar opposite strokes of :1V piston, theposition of the crank-throw at the mid-stroke of the piston is somewhatchanged as seen in Fig. 6. the depiction in regard to Fig. 3 being takenas a reference. Diameter cf denotes the piston pass, and the lowerbroken .circle represents the crankpin which is divided into four partsby the vertical linen-15 and a diameter v'- 7', lines -2: and 7c 7'being the two positions of the connector when the pistonis at itsmid-stroke. Each part is divided equally into equal number (forconvenience). and each half of the broken semi-circle which has pistonpass ef as a diameter is also equally divided into the same number asabove. Radii from crank shaft center 71 to the division points on circle0 i (l are drawn to represent the position of the crank-throw at severalstages of crank rotation. Horizontal lines perpendicular to piston passef from the dividing points on semi-circle cf are made. and the pointsof intersection thus obtained on piston pass c-f are connected with thecorresponding division points on thecircle. in the order up to down oneither side. indicating the position of the connecting rod at severalstages of crank rotation. From the connection length of the rod thusobtained, length e-c at the top forms for the present purpose.

nor as in Figs. 4 and but in this case, the

angles between the crank-throw and the connector are. not symmetrical onboth sides of the vertical diameter 0- 1 of Fi 6, so that the left side.angles in Fig. 6 are transferred on the right side of the line g-h ofFig. 7, separately from the right side angles which are transferred tothe left side of the vertical line g-Ji, and the two complementary camforms are drawi as in Figs. and 5 one over the other for the sake ofsimplicity. the inner broken circle corresponding to the circle of Fig.4 and the outer broken circle to the solid circle of Fig. 5 in findingthe centers of arcs. In applying to a crankpin, the lower side of themain cam profile 5 and the upper side of the auxiliary cam profile 6 areto be set toward the crank shaft. Mounting the cams as thus, if thecrank turns clock-wise, these cams are for a high speed engine. but ifcounter clock-wise, they are for a slow engine.

In Figs. 8 and 9, there is illustrated a my to determine cam profilesfor an offset engine, the similarity of the opposite strokes beingmaintained. The process of the profile formin g is briefly as follows:The points on piston pass e; are found as in Fig. 6. Point 0 is theintersection between crank-pin orbit c j (I 2' and straight line e c bwhich represents the position of the connector and the crank-throw atthe upper dead center. Straight lines 7 d and b d designate the positionof the connector and crank-throw at the bottom center. The diameter i bis the base of isosceles triangle is z' j Where 7? denotes the middlepoint of the piston pass. The four portions of the circle divided by c.2' '(Z and j are again divided equally into the same number as before,and these division points are joined with the corresponding points onthe piston pass as shown. The inclination angles and therequiredincrement are obtained. following to the manner described for Fig. 6,and cam curves are determined from these data,

as in Figs. 4, 5 and 7. J

In Figs. 10 and 11, cam profiles are presented. intended to give thepiston a long recess at each dead center. being a modification wherein achange is incorporated with the cam forms shown in Figs. 4 and 5. Thisfeature may he applied to any other cam In the figures, the period ofeach recess is taken at meow? ton are inner-shod by considering themodern origins in. which a lead or izig given (.0 the on? f a 1d closingof men waives; notably tlio exhaustionvalves no he opened. in zulvnniroWitl1 very'much loss or sacrifice of iii pnver siroka', tho-elm moreenergy e-Xolosion can be. nfilizaoo, and the exhaustion is made morecomplete, as 'ilie. piston roaches the top center long before tho vaivoolosas the full charge of fuel can be taken in before tho z in itsupward travel; and wmpres oi gas can be made. perfect 3 More the rippercenter is rot-ml. l so ohm. ie'ter ignition is effected is mlpeedengines.

the points on piston (3, and lower as in l horn-(21min 02 (Z whichincliczi. on tile left side i. half of a crank-pin pass is divid cl asfolows: At tho top and bottom. suitable angies (f c and (i L {11 aretaken for one half uvhndocl piston recesses nt- VG BITS. Lines c and alit no" n of stile oonrec' or at e' in 1 9 pi on i'scessos *ti 1 n o to)in low c met's, Wi; Z-i inclicn/uw the i si'lion the connector IOlii ornine piston.

oquully ilivuleai iii-o us many Are i (Z portions e division points areconneool with ,coi're poncling the mid-S i t upper senii oirclo is and pts on piston to designate tho position of tile connect-oi. at respectivestages of piston movement. The angles between til-e connectorcrank-throw, Whioh is roprowniod by the ru lii on before,- it respectivesing-us urn copioil on botl sides of g a oi 1.1 as in Fig. The requiroincre- 11 ours or (lCil'QlllPDiS of connection length to oluuiu thepinto: recesses are 'vll'lll obtained by ulggroln'uicnlly subtractinglength -ec from each conn ion length; if 2). c0nnoc- Lller than /:c, thediffer- Wilbl) is ialien us a fol lowing the process The connector more?\lil; to the way i (ionic-toil referring to 'lQsGli curves are (lrziwn 1mounting on a (ii-uni;- liL'CCEiOH is ilie as those in rription inlzonin panyiug (lrmringn.

u'tion and ur- EOQl oi? oporm will be readily" o 'sliosv mum in theail-"t i'o \Pill'iufi pertains, and While i in in no: .ul io theinvention in \vlmt lu' now thought. (0 b0 the best omlunlunout oi myinvention, 1 wish to have it llllllUl'HtUtKl that. the apparaiislltl'kli': shown uinl dosi-i'ilml is merely illustrative, and thatllieroforo i do not conlino n vwli to any slriut: conformity to theshowing of the (li';l\'fli1gfi but such changes or uunlilioutions maylie nnule, wlion desired, as to full within tlzo scope of the inventionas claimed.

liming EliLlS ilrsvrilioil my inwntion, what claim as no is:-

1. A connecting nmiiuui of Variable connection length for a crank and. ureciprocating member, comprising :1 rod mini :1 cum mechanism zuiuptmlto ,opei'uio between suiil rod and mi rrnnlgin response to angularvariation oi tho relative inclination between i lle rod and siiid crank,as herein substantially described.

la oons of modifying the rolutive movement. of :1 piston and, ucra-lnk-pin, comprising n cdi'inociing 11ml having :1 cum housing as anintegral piliil tlioruof. two kinds of sums mounted on said crank-12in.zunl cum followers on opposite .siiios of said cums,

5 ms being adapted to act or react cor- Eively upon said housing;through said C3111 follow-1 romting as ilio crank turns, and keepingcontinuous Contact with said cznn followers, thereby positively to varytliooonnecting; length of said rod in response to change of theinclination of said rod to the crank-thrm" carrying saio pin.

3. A connecmig medium between u connecting rod noel cm:si1ai't,'oo1nprising a coin mechanism oporg ied by relative angularchange between said yo and a throw of said crank-shaft, as the latterrotates, so as to vary the connection length of said rod wth respect tothe nosition of said throw.

A connector I01 1 nix-shaft and :1 pinion, comprising two kinds of oznnssecured with a throw of said cranlosln ft, and u :ocllnwing a (21mhousin which carries cam fOllGWQl"; on opposite sioeslof cums insubstantial ontinuous Contact tlxorowith Elie p1 'iles of said camsbeing related 'to' each other and to said coin followers. so us (0 lzoepthe distance between S-Ll(l followers substantially constant, and topositively vary the. connection length of said rocl, as said fink-shaftretains.

The COIill'2l .niion with a of a rod having" a cam bearing. and acrank-pin, comprising main and auxiliary coins which are ucinpiml to notor react corrolaiively on opposiio SKlPS upon sun. l) wing. so 39% tovary rho oo' nvcl'ion longili o and rod. wuen or uid, cams beifinbioonly'in ilzo (liructi n of lilo roii in rontact v. i mid iiouiing.

Tlio 'ubinniion with 21 in, ii?!" I ".culzn a I: l (n u (mini-i. ilions, and ii conneo rod inn ing therefor, the profiles of said camportions being such as to reciprocally move said rod, relatively to theaxis of said pin, with the circular portions resisting the lateral1notion of said bearing, in response to change of the inclination ofsaid connecting rod to the crank-throw carrying said crank-pin.

7. Means of attaching a connecting rod to a crank. comprising a shaftcarrying cams, and a cam bearing, integral with said rod, havinganti-friction rollers on opposite sides of said cams, the profiles ofsaid cams being related to one another and to the rollers, so as to movethe bearing reciprocally with respect to said shaft in response to theangular change of-position of the ci'ank carrying said shaft withrespect to said rod, keeping the distance between said rollerssubstantially constant.

8. A crank-piston connector of variable connection length, comprising acrank-pin having cams and plates, a rod having a housing as an integralpart thereof, and cam followers held in said housing continuously"engaging with said cams on opposite sides of the latter, said housinghaving openings to admit said crank-pin to reciprocally move therein,and said plates having washers held thereby and adapted to slide incontact with the wallof said housing so as to keep said openingssubstantially closed.

9. The combination with a crank shaft; of a crank-pin rigid therewithhaving two kinds of cams, and a cam housing having cam followers onopposite sides of said crank-pin in engagement with respective cams,said cams being adapted to act or react upon the housing in response toangular change of position between said housing anda crank of said crankshaft.

10. A cam mechanism, comprising a cam shaft, having two kinds of doubleapex cams, and a housing therefor having cam followers on opposite sidesof the cams, said cams having predetermined profiles to act correla- 4tively on opposite sides, varying with the rotation thereof theelevation of said followers oppositely from the axis of said shaft, sothat the distance between said followers is kept constant.

In testimony whereof I'afiix my signature in the presence of twosubscribin NAWOKICHI TiNAKA.

Witnesses V LOUELLA D. Evm'rr,

VIRGIL A. CHARLES.

witnesses.

